This study is about a drug called lenacapavir (LEN) for treating young people with HIV-1, a virus that affects the immune system. The study checks if the drug is safe and how well it works when combined with other medicines. It is for kids and teens who weigh at least 35 kg (about 77 pounds) and have tried other HIV-1 treatments before. The study will see if taking LEN as a shot or pill is easy for them.

• The study involves taking LEN with other HIV medicines and will last a few months.
• Participants must have tried other treatments and weigh at least 35 kg.
• Those with certain health problems, such as active tuberculosis, cannot join.

If you are interested, you should be prepared to take the medicine regularly and attend visits for the study. The study helps understand how well LEN works and how safe it is for young people with HIV-1.